Support for passing an array of styles as extra attributes

[misaf]

This PR adds support for passing an array of styles when rendering a Media Model:

Media::first()->img('thumb', ['styles' => [
    'background-color: blue',
    'color: blue'
]]),

Under the hood, it uses Laravel's Arr::toCssStyles helper method.

[freekmurze]

Could you add a tests and documentation for this?

[misaf]

Sure, I'll make sure to add tests and documentation for this feature.

[misaf]

Tests and documentation have been added as requested.

[freekmurze]

It seems the tests are failing. Could you have a look?

[misaf]

All tests are green!

[freekmurze]

Thanks!